A mother of 12 has pleaded guilty to wilfully neglecting her eight youngest children so that they were likely to suffer unnecessarily.

The woman was last week discharged on other allegations that she had sexually abused some of the children.

The trial against her and three others in the High Court at Wellington collapsed last week. The woman, the children's father, the woman's cousin and a friend were cleared of all allegations – except the parents still faced cruelty charges.

A judge said the children's claims of sex abuse and assaults had been discredited and were unreliable. He had to end the trial to protect against the danger of unsafe convictions, he said.

In court yesterday the mother's eight cruelty charges - one relating to each of the children - were changed to a single charge covering the children and the woman, 42, pleaded guilty.

She was remanded on bail for sentencing next month.

The charge related to about four months after she gave birth to the youngest child. The children, then aged four months to 10 years, were removed from her care in March 2010.

At the time the father, now 55, was on a bail condition not to live with his family due to charges that he committed indecencies on one of his partner's older children.

He is back in court again later this week for about a hearing about the cruelty charges he still faces.